USS Potomac is a preserved Coast Guard cutter best known as Franklin D. Roosevelt's presidential yacht. It is moored at Jack London Square, where visitors can usually see it on a dockside tour, with seasonal cruises adding a broader view of the bay.
The ship is a worthwhile stop for history-minded visitors in Oakland, especially if you are already spending time along the waterfront. Check tour and cruise schedules before going, since access depends on volunteer operations and seasonal sailings.